Apparatus for filling containers in a vacuum environment



United States Patent [72] Inventor Clarence F. Carter [56] References Cited 2| A l N UNITED STATES PATENTS 1 P 2,765,816 10/1956 Carter 141/51x [22] Filed April 16, 1968 2,799,465 7/1957 Carter..... 141/10X [45] Pa'emd 1970 3 147 616 9/1964 Rome 117/20sx [73] Assignee Cater Engineering Company Danvillelllinois 3,371,732 3/1968 Stem 177/208 a corporation of Illinois Primary Examiner-Laverne D. Geiger Assistant Examiner-Edward J. Earls Attorney-Burns, Doane, Benedict, Swecker and Mathis [54] APPARATUS FOR FILLING CONTAINERS INA ABSTRACT: A weighing and filling apparatus including a VACUUM ENVIRONMENT 4 Cl ms 4 D Wi Fi housing, a weighing cage suspended within the housing from a a m pneumatic load cell, means for generating a vacuum within [52] 0.8. CI. 141/65, the housing, and means for conveying particulate material to a 141/68, 141/83, 141/314, 177/208, 177/238 container supported by the weighing cage. The pneumatic [$1] lnt.Cl. B65b 3/04 load cell includes a flexible seal exposed to the vacuum en- [50] Field of Search... 141/51, 10, vironment within the housing and additional diaphragm means 65,67, 68, 83,313317; 177/180-182, 208, exposed to the vacuum and operable to nullify vacuum 209, 238 generated forces acting on the pneumatic load cell.

' as oo o o o 3- Patented Nov. 24, 1970 3,542,091

Sheet Z of 2 F|G 38 29 v o 0 FIG. 2

, INVENT OR CLARENCE F CARTER ATTORNEYS,

Patented Nov. 24, 1970 3,542,091

Sheet 2 01'2 FIG. 4

OUTPUT 8 2 SIGNAL To ATMOSPH ERE FLOW REGULATOR ATMOSPHERE 89 INVENTOR AIR CLARENCE E CARTER SUPPLY ATTORNEYS.

APPARATUS rota FILLING CONTAINERS m A VACUUM ENVIRONMENT BACKGROUND, GENERAL OBJECTS'AND SUMMARY OF INVENTION -For some time the'advantages of filling containers in a vacuum environment has been recognized. A pioneer contribution in this art is evidenced by a U.S. Carter Pat. No. 2,765,816.

The apparatus featured in this Carter Patent is characterized by a weighing cage supported by a linkage which extends through a bellows seal to a beamtype weighing device mounted externally ofthe housing.

The advantages of this unit notwithstanding, certain problemsare presented by employing mechanical force transmitting means to passthrough the housing wall to an external weighing device. For example, special seals are required where the mechanical linkage intersects the housing. Such seals, even though small, engender weighing errors in that they are acted upon by a vacuum environment within the housing.

While compensation can be made for the vacuum effect, it would be desirable to altogether eliminate the effect of vacuum on the weighing operation.

Other problems are often involved in the handling of powder materials which are flammable or explosive in character because of their finely divided nature. Electrical control circuits in the vicinity of an apparatus effecting the filling of a container with such material might constitute a safety hazard in that is would introduce the possibility of sparking which could ignite the finely divided material.

Because of the environmental conditions surrounding the weighing and filling operations, and because unskilled personnel are often involved in the handling of filling apparatus, it would be desirable to fully shield a weighing apparatus incorporated with a filling mechanism.

It thus is an object of the invention to provide an apparatus for filling a container in a vacuum environment while ensuring that the vacuum does not deleteriously affect the weighing ofa container being filled.

It is likewise an object of the invention to positively protect and shield a weighing mechanism-incorporated in a filling system by fully housing the weighing mechanism within the filling unit interior.

Another object of the invention is to provide a pneumatic or fluid responsive weighing unit lacking altogether the seal problems associated with mechanical'or beamtype weighing units and lacking altogether the safety problems engendered by electrical weighing units.

In a seemingly contradictory manner, it is an object of the invention to incorporate'such a fluid responsive weighing system in an environment where the weighing mechanism is acted upon by external forces generated by a vacuum, which forces are not related to the weighing operation.

In accomplishing at least some 'of the foregoing objects, there is presented through the invention an apparatus which includes housing means and first conduit means operable to create a vacuum within the interior of the housing means. A container supporting means, i.e., weighing cage, is disposed within the housing means. A nozzle means projects through a wall portion of the'housing means and includes second conduit means operable to convey particulate material to a container supported by the container supporting means. A container weighing means is included in the apparatus in combination with a shroud means which defines a portion of the housing means and encloses the weighing means within the housing means interior.

A force transmitting means extends from the container supporting means to the weighing means and is operable to transmit the weight of the container supporting means and a container supported thereon to the weighing means. Fluid reaction surface means are operable to generate oppositely directed forces acting on the force transmitting means to nullify the effect of a vacuum environment in the interior of the housing means on the weighing means.

DRAWINGS In describing the invention, reference will be made to a preferred embodiment shown in the appended drawings.

In the drawings:

FIG. 1 provides a fragmentary, vertically sectioned, elevational view of a weighing device of the present invention illustrating structural details existing between a filling nozzle, a weighing cage, a vacuum environment and a pneumatic weighing cell;

FIG. 2 provides a top plan view of the FIG. I assembly illustrating a housing dooropened and a weighing cage door opened to facilitate the installation of a container in the cage for filling purposes; 1

FIG. 3 provides a sectioned, top plan view of the pneumatic load cell incorporated in the FIG. 1 apparatus; and

FIG. 4 provides a vertically sectioned, elevational view of the pneumatic load cell as viewed along the section line 4-4 of FIG. 3.

PRINCIPAL COMPONENTS OF APPARATUS FIGS. 1 and 2 illustrate and filling apparatus 1.

Apparatus 1 includes a cabinetlike housing 2. A conduit 3 extends from housing 2 to a vacuum pump, not shown. Conduit 3 thus serves as a vehicle for withdrawing air from the interior 4 of housing 2 so as to produce a vacuum in this housing cavity 4.

A cagelike, bag container 5 is supported for vertical weighing movement within the housing cavity 4. A material supplying 'nozzle 6 projects through a wall 7 of the housing 2. Nozzle 6 serves to convey particulate or powered material into an upper corner of a bag supported by the weighing cage 5. A flexible coupling 8 allows the nozzle tip 9 to undergo vertical movement with the weighing cage 5 and a container supported thereby without adversely affecting the weighing operation.

' Structural details of the nozzle 6 and flexible connection 8, as well as detailed considerations of the manner in which these mechanisms serve to supply particulate material to a container within the cage 5 are set forth in the aforesaid U.S. Carter Pat. No. 2,765,816.

In this connection, reference may be made to FIG. 2 in order to obtain a better understanding as to how a container to be filled is loaded within the cage 5. Cage 5 includes an L- principal components ofa weighing shaped assembly 10 including a front wall I1 and a left side By opening the cabinet door 20, and pivoting the cage door 10 outwardly, a bag may be moved into the interior of the cage 5 with the nozzle end 9 received within the upper right corner of the bag. The cage door 10 is then closed and latched, following which the cabinet door is closed and latched. Thereafter a vacuum is induced in the cabinet interior 4 by means of withdrawing air through the conduit 3. Particulate material may be then conveyed into the bag through the nozzle 6.

The vacuum within the interior zone 4 facilitates the filling operation by removing air which might tend to make it difficult to obtain a dense packing of material within the container being filled. The vacuum also serves to hold the sides of tion Ser. No. 549,709., f led May l2, 1966, now US. Pat. No.

3,430,720 and entitled, Methods and Apparatus for Weighing Materialin Vacuum Enviornment".

Apparatus 1 further includes a pneumatic weighing cell 23. A cylindrical shroud 24 covers the weighing cell 23 and, in essence, defines a continuation of the housing). As will be apparent, with reference to FIGS. 1,3 and 4, cell 23 is supported on brackets 25 and'26 which extend across an aperture 27 in extending side legs 31 and 32. A horizontally'extending top beam 33 interconnects the'side legs'3l and 32 and passes across the top of the load cell. Top member 33 is operable to transmit the weight of thecage and a container being filled totheloadcell23. I

As illustrated, bracket legs 31 and 32 are connected to a top strut 34 of the-cage body 14. The connecting points 36 and 37 between these legs and the strut are centrally and symmetrically located with respect to the closedcage 5 so as to provide a symmetrical and uniform transmission of load from the cage 5 to the bracket member 33.

A pneumatic signal generated by the load cell 23, which is directly proportional to the weightof the container being filled within the cage 5, is transmitted to aconventional recording and indicating mechanism 38. v

Thus, as a container within the cage 5 is being filled by the nozzle 6, the corresponding weight of the cage 5 is transmitted through the bracket30 to the weighing cell 23. A pneumatic pressure signal generated within the load cell 23 is proportional to the weight of the container being filled and is transmerits, and rod means segments are interconnected by conventional fastener means (not shown) which pass vertically through the stacked elements.

The uppermost or first diaphragm 60 defines a flexible closure for the upper end of the weighing cell 23.

A second diaphragm 61 is disposed axially beneath diaphragm 60 so as to define a first cavity 62. The areal extent of diaphragm 61 is less than that of diaphragm 60.

A conduit 63 serves to provide controlled pressurized air to the first cavity 62. The pressure of 'air fed through the conduit 63 may be regulated by a conventional pressure regulator 64. This regulated pressure supplied to the cavity 62, because of the difference in area of diaphragms 60 and 61, provides a net, upwardly. biasing'force, transmitted through the diaphragm 6.0 and 61 to the rod means 48. This force is calibrated by controlling the applied fluid pressure so as to offset the tare weight of the apparatus, i.e., to offset or compensate for the weight ofthe cage 5; etc."

A third. diaphragm 66 is disposed axially beneath the diaphragm 61 so asto define a second cavity 67. Cavity '67 communicates with the atmosphere external of the housing 2 by way of the conduit 68. I A fourth diaphragm 69 is spaced axially beneath the diaphragm so as to define a third chamber 70. Chamber 70 is disposedin direct communicating relation with the vacuum environment, created in the housing cavity 4, by way of one or more ports 71 formed in the segments 44.

The areal extent of the diaphragm 66 exceeds that of diaphragm 69.'The difference of the effective areal extent of the diaphragms 66 and 69, including portions overlapped by mitted to the indicator38. Thus, an operator can determine the amount of material tainer. v. Conventional control means may extend from the'indicator 38 to effect the automaticterminationof filling, once a required containerweight has been achieved.

As will be noted, the load cell 23 is entirely enclosed within the interior 4 of the cabinet 2. Within the interior of the which has been supplied to the con-v cabinet there are no electrical components which would e'nfluid responsive rod segment portions, is equal to the effective areal extent of the diaphragm 60. Thus, vacuum acting on the diaphragms 66 and 69 within the cavity 70 imposes a net downward force on the rod means 48 which is exactly equal to the net upward force imposed by this vacuum on the rod means 48, as transmitted through the diaphragm 60. In this manner, the vacuum induced force acting on the upper side of the diaphragm 60 isnullified. I v A, fifth diaphragm-unis disposed axially beneath the 1 diaphragm 69 so as to def ne a fourth cavity 73; A sixth ages pass through the housing wall, no special seals are required.

DETAILS OF PNEUMATIC WElGl-llNG CELL FIG. 4 illustrates structural details of the pneumatic cell 23.

Load cell 23 includes generally cylindrical enclosure means 39 defined by a series of stacked, generally annular segments 40,41,42,43,44,45,46 and 47. e

A force transmitting rod means 48 is mounted for limited force transmitting, vertical movement within the interior of the enclosure 39. Rod means 48 is comprised of a series of stacked rod segments 49, 50, 51, 52, 53, 54, and 56.

A spherical ball bearing 57 provides a force transmitting mechanism between the bracket beam 33 and the upper end 56 of the rod means 48. As illustrated, ball bearing 57 is received within a conforming ball seat 58 formed in the underside of the member 33and a conforming ball seat 59 mounted in the top portion of the'upper rod member 56.

Load cell 23 includes a series of annular diaphragms exdiaphragm 74 is disposed beneath the diaphragm 72 so as to define a fifth cavity 75. Restricted portmeans 76 intersects the diaphragm 72 and flange portions of the segments 51 and 52'so as'to provide limited communication between the cavities and 73. These cavities 73 and 75 are filled with oil. Thus, the port 76 allows the diaphragm 72to undergo dampened movement within the cavities 73 and 75.- This dampening stabilizes the weighing movements of the rod means 48.

A seventh diaphragm 77 is disposed axially beneath the diaphragm 74 so as to define sixth cavity 78. Cavity 78 communicates with the atmosphere by way of conduit 79 which branches laterally from conduit 68. m

A lower end wall 80 forms the base of th enclosure 39. An orifice 81 is centrally located in this wall means 80. A conduit 2 provides fluid communication between the orifice 81 and the atmosphere external of the housing 82. An orifice vflow controlling assembly 83 is'carried by the segment 49. This flow controlling unit 83 comprises a plate 84 supported on a rim 85 and biased downwardly by a coil spring 86. with this.

' 87. A conduit 88 serves to supply pressurized air to the cavity tending between the rod means 48 and the enclosure means 87 under the controlling influence of the-conventional pressure andconstant flow regulator 8 9. In this manner, a constant feed of regulated pressure air is supplied to the cavity 87 A conduit 90 provides a outflow path from the cavity 87, leading to a conventional pressure recording component of the mechanism 38.

As will be appreciated, when a load is imposed on the beam 33 by the cages and a container being filled, the rod means 48 will be depressed so as to cause the plate 84 to close the orifice a .5. 81. This will cause pressure tobuild up withinthe-cavity 87 to a point sufficient to overcome the load: force acting on the load means 48 which inducedits depression. This pressure increase will betransmitted' through theconduit 90 tothe recorder 38; The magnitude'of the pressureincrease will be directly propo'rtionalto' the weight of the container being filled. ln'this 'connectiom iewill be appreciated that'thetare weight of the cage S-arid the vacuumforcesacting-on theloadmaterial may irnposea nonsymmetrical loacl on'.theeage i'lnorder to ensure that this nonsymmetrical'loadis 'transrnitted axially and centrally to the rod means48, a centeringto'r restraining mechanism 91 is provided. Centering mechanism 971 comprises an annular washerl92 whichperipherally encircles the ball 57. The central aperture 93 of the washer 92 slightly exceeds the diameterjof the ball 57 so as tov provide lateral restraint of .the ball 57"while. allowing vertical ball movement to take place in accordance with loads acting on the beam 33. I v

Restraining washer 92 is held in space insu'ch a manner as not to impose'any load'on the rodmeans '48. This'suspension is achieved by a series of chains 94 whichare connected to the periphery of the washer 92 ata connecting point 95:..Each

chain 94 extends horizontally outwardly to a bracketmounting 96 at the rim 47 ofthe enclosure means 39.

SUMMARY OF ADVANTAGES AND .S'CQPE-OF fies vacuum forces acting on the rodmeans48, the weighing cellis able to accurately perform its weighing function without being affected by vacuum conditions.

This unobvious "and unique utilization of a pneumatic weighing cell in a vacuum environment affords theadv antage of completely avoidingithe safetyproblems which wouldbe engendered by electrical'wei ghing units and'completely avoiding the seal problems which would be associated with mechanical weighing'units. in describing the invention, reference has been made t'o'a preferred embodiment. Howeven'those sltilled the vacuum filling art may envisionvadditions, deletions, subs-titutions or other modifications'which would fall within the purviewof the invention as set forth in the appendedclairns. V

lclaim: 1. An apparatus for filling containers with particulate material in a vacuum environment said apparatus comprising:

housing means; t first conduitmeans operable to'withdraw air fromthe interior of said housing means; container supporting'means disposed within .said housing means; y nozzle meansprojec'tingthrough a.wall portion of said housing means'from the exterior of the'housing means into the interior thereof, said nozzle means including second conduit meansoperableto convey particulate material to a containersupportedbysaid containersupporting means: container weighingmeans;

. 45 Through the unique diaphragm arrangement; which nulli- I 6 shroud means having an interior'communicating with the interior of said housing meansso as to define a portion thereof, and enclosing said weighingmeans within the interior of said housing means;

force transmitting means extending from said container supporting means'to saidweighing means and operable to transmit the weight of said container supporting means and a container. supported thereon to said weighing means; and i 10 fluid reaction surface means carried by said force transmitting means and operable to generate oppositely directed forces acting on said force transmitting means to nullify the effect of a vacuum environment in the interior of said housing means on said weighing means.

2. An apparatus, forfilling containers with particulate material in a vacuum envi'ronment','said apparatus comprising:

housing means; firstconduit means operable to withdraw air from the interior of said housing means; container supporting means disposed within said. housing means; nozz leimeans projecting through a wall portion of said hous- I ing meansfrom the exterior of the housing means into the interior thereof, said nozzle means including second con- I duit means operable to' convey particulate material to a container supported by. said container supporting means; container weighing means;

shroud means having an interior communicating with the interiorof said housing means so' as to define a portion thereof, and enclosing said weighing means within the interior of said housing means;

' force transmitting-means extending from said container supporting. means to said weighing means and operable to transmit the weight of said container supporting means --,and a container supported thereon to said weighing means;

i said weighingmeans including:

first, fluid reaction surface means connected with said force transmittingrmeans and exposed'to a vacuum created within the interior of said housing means by the withdrawal of air'through said first conduit means; and second; fluid reaction surface means connected with said force transmitting means, said second fluid reaction surface meansbeing exposed to said vacuum and operable to impose a vacuum induced force on said force'transmittingrneans opposite to a force imposed on said first, fluid reaction surface means by said vacuum; said first fluid reaction surface means providing a flexible -closure for a portion of said weighing means, with said closure-being exposed to said vacuum.

3. An apparatus for filling containers with particulate I material in a vacuum environment, said apparatus comprising: housing means:

first conduit means operable to withdraw air from the interiorof said housing means; container "supporting means disposed within said housing means; nozzle means projecting through a wall portion of said hous- -ing means from the exterior 'of the housing means into the interior thereoflsaid nozzle means including second conduit means operable to convey particulate material to a container supported by said container supporting means; cylindrical shroud means having an interior communicating 4 with the interior of said housing means and defining a detachable portion thereof; generally cylindrical enclosure means mounted on an upper portion of the interiorof said housing means; a generally U-shap'ed bracket having:

a pair of legs passing vertically along opposite sides of said enclosure and connected with said container supporting means; and

a horizontally extending end member connecting said legs and passingover the top of said enclosure;

.force transmitting rod means positioned within-said enclosure means for limited vertical-movement; force transmitting means between said horizontally extends ing end member of said U shaped bracket andsaid rod means and-including a spherical ball interposed axially between said end rnember'and said rod means;

first, annular diaphragm mean extending between said rod means and said enclosure -means,.,said first diaphragm means defining a flexible closure for the upperiend of said l means, said second diaphragm. meansj being located beneath said first diaphragm means;

first cavity meansdisposedaxiall be ween 'said first and second diaphragm means;

means operable to supply fluid pnessurefto said first cavity I means with said-fluid-pressure' ctmg Ion said first' t and diaphragmmeans to-exertia net lifting force on-said rod means 'to compensate.

for'fthe weight of 'said container supportingmeans,

7 third, annular diaphragm means extending between said rod means and said enclosure means and disposedaaxially beneath said second diaphragm means; second cavity meansinterposed between said second and third diaphragm means; v o i third conduit means providing fluid communication between the atmosphere external of said housing means and said second cavity means; a 3 1 I 1 fourth, annulardiaphragmmeansextending between said rod means and said enclosure means and disposed beneath said third diaphragm means;

third cavitymeans interposed axially between said third and fourth diaphragm means, said third cavity means being disposed in fluidcoinmunicating relation with the interior ofsaidhousingmeans; I said fourth diaphragm means'having anarea less than that of said third-diaphragm means, with the difference in area between said third'and fourth diaphragm means-being equal to the effective area-of said first diaphragm means to cause vacuum w thin the interior of said housing means acting on said first diaphragm means to produce a force acting on said rod means-opposite to the net vacuum-in-' duced force imposed on said rod means by saidthirdand fourth diaphragm means; i v g fi annular iap gm means extending between said rod fifth conduit means operable to 8 means and said. enclosure means and disposed axially beneath said fourthdiaphragm means;

fourth cavity means interposed 'xially between said fourth and fifth diaphragmmeans; f i

sixth, annular diaphragm means extending between said rod 'means and said. enclosure means and located axially beneath said fifth diaphragm means;

fifth cavity means .interposedlaxially between said fifth and "sixth diaphragm means; 7 r g Y restricted port means providing limited fluid communication between said fourth'andfifth cavity means so as to .permit' motion .dampening movement of said fifth diaphragm-within'said fourth and fifth cavity means;

' seventh; annular diaphragm means extending between said 15 seventh diaphragm means; I

vv fourtl'l conduit means providing fluid communication 20.. second diaphragm means to cause said firstand' second seventh cavity means interposed axially between said seventh'diaphragm-means and said wall means;

orifice means mounted in said wall means;

orifice restricting means carried by said seventh diaphragm means and operable; to ,vary flow through said orifice means in response to axial movement of said rod means;

- means operable to supply regulated fluid pressure to said seventh cavity means;

discharge fluid from said seventh cavity means through said orifice means'and to the atmosphere external of said housing; and signal conduit means operable to transmit-the pressure of v fluid within said seventh cavity means to pressure measuring means. 4. An apparatus as describedin v annular constraining means horizontally encircling said spherical ball anddisposed in vertical telescoping relationship with saidball so as to allow saidball to move verclaim 3 including force transmission stabilizing means comprising: 

